Passenger conveyor drive mobile arrangement

ABSTRACT

A passenger conveyor system ( 20 ) has a drive module that engages only one side ( 50 ) of the step chain loop ( 30 ). In a multiple drive module arrangement, at least one of the drive modules ( 40 B) engages both sides ( 50, 52 ) of the step chain loop while another engages only one side ( 50 ). The inventive arrangement is not sensitive to spacing ( 54, 56 ) between the drive modules. Another example embodiment includes a synchronizing module ( 60 ) that engages both sides ( 50, 52 ) of the step chain loop ( 30 ).

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention generally relates to passenger conveyors. Moreparticularly, this invention relates to drive modules for passengerconveyors.

2. Description of the Prior Art

Passenger conveyors are well known and in widespread use. Escalators ormoving walkways typically include a plurality of steps that move along apath to carry passengers from one location to another such as betweenfloors in a building. Typical arrangements include a step chain having aplurality of links associated with the steps. The step chain moves in aloop corresponding to the loop followed by the steps. A drive moduleengages the step chain to cause the desired movement of the steps.

In modular conveyors, more than one drive module can be used to carrythe anticipated passenger load, for example. Instead of using largermotors to compensate for the length of the passenger conveyor or thesystem construction, multiple drive modules may be employed. Passengerconveyors having multiple drive modules are known.

There are difficulties in utilizing more than one drive module for apassenger conveyor. One problem is associated with the spacing betweenthe drive modules. If the spacing is not accurately controlled, the loadcarried by each drive module is not equal, increasing wear in thehigher-loaded module(s). Further, even when accurate spacing isachieved, changes in the system over time (i.e., wear on systemcomponents or material contraction or expansion due to environmentalfactors) requires periodic maintenance and adjustment. Without accuratespacing between the drive modules in conventional arrangements, theportions of the step chain between the drive modules see varying amountsof compression or tension, depending on the situation.

U.S. Pat. No. 4,397,096 presents one proposed solution to this problem.That patent describes a device for measuring compression or tension onstep chain links to determine whether the spacing between drive modulesis accurate. While such a device may facilitate placement of the drivemodules or adjustment of the modules over time, the difficulty ofaccurate placement and load distribution among the drive modules stillexists. Even with such a device, there are additional expensesassociated with the maintenance and inspection of the escalators.

Conventional arrangements include a steel truss for supporting theelevator. The truss typically includes a track or other structure forguiding the step chain links along a chain loop. Such conventionalarrangements Limit the materials that are useable for making the stepchain links. Specifically, steel must be used for the step chain linksto avoid different thermal expansion properties between the chain andthe truss. With differing materials having differing thermal expansionproperties, the tension on the drive chain may change responsive to achanging environment, which then necessitates further adjustment of theescalator drive system. Making such adjustments is impractical and,therefore, conventional arrangements have only included the samematerial used to make the escalator truss structure and the step chainlinks.

There is a need for an improved arrangement that allows using multipledrive modules for a passenger conveyor. This invention provides a systemthat eliminates the need to control the spacing between the modules,avoids uneven distribution of forces between drive modules and overcomesthe shortcomings and drawbacks of the prior art described above.

SUMMARY OF THE INVENTION

In general terms, this invention is a passenger conveyor with a drivemodule arrangement that permits more convenient and economical use ofmultiple drive modules.

One system designed according to this invention includes a plurality ofsteps that are moveable along a step loop having a passenger side and areturn side. A step chain is associated with the steps. The step chainis moveable along a chain loop having a first side corresponding to thepassengers side of the step loop and a second side corresponding to thereturn side of the step loop. At least one drive module has a motor anda drive member that engages the step chain only on one of the first sideor the second side of the chain loop. The motor moves the drive memberto cause selective movement of the chain and the steps.

In one example system a second drive module has a motor and a drivemember that engages the step chain on both sides of the chain loop.

In another example, a synchronizing module has a synchronizing memberthat engages the step chain on both sides of the chain loop.

A method of moving a step chain in a passenger conveyor system designedaccording to this invention includes providing a drive module that has adrive member that is adapted to engage only one side of the step chainto apply a motive force for moving the step chain along the loop.

The various features and advantages of this invention will becomeapparent to those skilled in the art from the following detaileddescription of the currently preferred embodiments. The drawings thataccompany the detailed description can be briefly described as follows.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 schematically illustrates a passenger conveyor system designedaccording to this invention.

FIG. 1A is a cross sectional view taken along the line 1A in FIG. 1.

FIG. 2 schematically illustrates a first example embodiment of apassenger conveyor system designed according to this invention.

FIG. 3 schematically illustrates a second example embodiment of apassenger conveyor system designed according to this invention.

FIG. 4 schematically illustrates a third example embodiment of apassenger conveyor system designed according to this invention.

FIG. 5 schematically illustrates a fourth example embodiment of apassenger conveyor system designed according to this invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 schematically illustrates a passenger conveyor system 20, whichis an escalator in this example. This invention, however, is not limitedto escalators but is applicable to other types of passenger conveyors,such as moving walkways. The illustrated passenger conveyor system 20includes a plurality of steps 22 that are moveable along a loop so thatthe steps 22 carry passengers between landings 24 and 26.

A truss structure 28 supports the escalator system components in a knownmanner. The truss structure 28 in one example is made primarily of steeland accommodates movement of the steps 22 along a path that has apassenger carrying side (illustrated) and a return side (notillustrated). As known, the return side of the step loop typically ishidden within the truss or other structure surrounding the conveyorsystem components.

A step chain is associated with the steps 22 and moves along a loop 30.The step chain includes a plurality of step chain links 32. The stepchain is supported by appropriate portions of the truss structure 28 sothat it is moveable along the chain loop 30 in a known manner.

A drive module 40 propels the step chain and the steps 22 as required tomove passengers between the landings 24 and 26. The drive module 40includes a motor 42 that causes a drive sheave 44 to rotate at a desiredspeed. Movement of the drive sheave 44 causes movement of a drive member46, which engages the step chain for moving the steps 22 as desired. Anidler sheave 48 supports an opposite end of the drive member 46. In oneexample, the drive member 46 is a drive chain. In a preferredarrangement (schematically shown in FIG. 1A), the drive member 46 is abelt made from a plurality of load-bearing cords 47 imbedded in urethanematerial 49. The drive member 46 preferably has an exterior surface thatis contoured to provide the appropriate non-slip engagement with thestep chain. Those skilled in the art who have the benefit of thisdescription will be able to select or design a drive member to meet theneeds of their particular situation.

As best appreciated from FIG. 2, the step chain loop 30 includes a firstside 50 that corresponds to the passenger side of the step loop and asecond side 52 that corresponds to the return side of the step loop.Only selected portions of the escalator system 20 are schematicallyshown in FIG. 2. This example arrangement includes a first drive module40A and a second drive module 40B that each provide a motive force formoving the step chain along the chain loop 30. The drive module 40Aengages the step chain only on the first side 50 of the step chain loop30. The drive module 40B engages both sides 50 and 52 of the step chainloop 30. Having a drive module that engages only one side of the stepchain loop 30 is a significant departure from conventional arrangements.Module 40A could engage step chain loop 30 only on second side 52, butthat would increase load on the belt at the drive module 40B.

With the inventive arrangement, the spacing between the drive modulesneed not be tightly or accurately controlled as was required inconventional arrangements. The portions of the step chain shown at 54and 56 will not experience changes in compression or tension (due todrive module position changes, wear or thermal expansion) because thedrive module 40A imparts a force F1 only to first side 50 of the stepchain loop 30. This invention provides the advantage of not having toprecisely control the spacing between the drive modules and, instead,allows for greater freedom and variability of placement of the drivemodules within the confines of the escalator system.

With conventional arrangements having multiple drive modules, the weightsupported by each module is indeterminant. The forces associated witheach drive module introduce more variables than can be solved (based onthe known relationships) and, therefore, accurate force determination ateach module is not possible and more complicated adjustment routines arerequired.

In contrast, the inventive arrangement provides a statically determinantsystem that is not sensitive to the spacing between the drive modules.The inventive arrangement provides a system that can be described byfive equations with five variables. Therefore, the inventive arrangementis a determinant system with an equal number of variables and equations,which is solvable. The tracks (not illustrated) that guide the stepsaround the turnarounds preferably are designed so as to not carry anysignificant load so that the following equations may be used. Such adesign avoids any force transfer between the passenger and return sidesof the step chain except through a drive module that contacts bothsides.

For example, the belt 46A of the drive module 40A applies a force F, andthe belt 46B of the drive module 40B applies a force F₂, both on thefirst side 50 (i.e., the passenger side) of the step chain loop 30 inthe example of FIG. 2. The following equations describe the system:F ₁ +F ₂ =F _(P) +F _(PS);F₃=F_(RS);F _(MOTOR1) =F _(MOTOR2)(for matched motors);F _(MOTOR2) ═F ₂ −F ₃; andF_(MOTOR1)=F₁;where F₃=the force from the belt 46B applied to the second side 52(i.e., the return side) of the loop 30; F_(P)=the weight of thepassengers; F_(PS)=the weight of the passenger side steps and chain;F_(RS)=the weight of the return side steps and chain; F_(MOTOR1)=theforce applied to the belt 46A by the MOTOR1 of the drive module 40A; andF_(MOTOR2)=the force applied to the belt 46B by the MOTOR2 of the drivemodule 40B.

With the inventive arrangement the load imposed on the step chain by themodules that engage only one side of the chain loop 30 is the motortorque divided by the effective pulley radius. That load is determinableusing the known relationship between the motor torque and the speed ofchain movement.

In one example arrangement, the drive module that engages both sides ofthe step chain loop 30 includes a smaller motor to equalize the forcetransferred from the drive module to the passenger side at each module.The drive module (i.e., 40B) that engages both sides of the step chainloop 30 applies motor torque to the passenger side of the step chain andtransfers the weight of the return side of the loop 30 to the passengerside (i.e., the first side 50). In this example, the smaller motor ofthe drive module that engages both sides, therefore, allows for an equaldistribution of force applied to the passenger side of the step chainloop at each drive module.

The spacing between the second side 52 of the step chain loop 30 and thedrive module 40A may be accomplished as illustrated in several ways. Inone example, the drive modules are the same size but the spacing betweenthe passenger side and the return side of the tracks (not illustrated)that guide the step chain loop 30 is increased in the vicinity of thedrive module 40A. In another example, the spacing is accomplished byutilizing a smaller sized drive module 40A compared to the drive module40B. The size of the sheaves 44A and 48A are smaller than the sheaves44B and 48B. Similarly, the drive member 46A could be smaller, or thesheaves 44A and 48A could be slightly farther apart. This providesadditional advantages of allowing the use of smaller components, whichintroduces space savings and other enhanced system economies such aslower motor torque and more system design flexibility.

Another advantage of this invention is that it makes it possible to usedifferent materials for malting the step chain links 32. For example,aluminum is one desirable material because of its light weight andcorrosion resistance properties. With the inventive arrangement,different expansion rates between the link material (i.e., aluminum) andthe truss or guide material (i.e., steel) do not cause complications.

Although not specifically illustrated, in another example arrangement,the drive modules 40A and 40B are the same size and the step chain looppath is diverted away from one side of one of the drive modules so thatthe drive module engages only the first side 50 of the step chain loop30. Those skilled in the art who have the benefit of this descriptionwill realize the most effective way to achieve the spacing requiredbetween a drive module and a step chain so that the drive module engagesonly one side of the step chain to meet the needs of their particularsituation.

FIG. 3 illustrates another example arrangement where the drive module40A engages both sides 50 and 52 of the step chain loop 30 while thedrive module 40B engages only the first side 50 of the step chain loop30. The placement of the drive modules can be varied depending on theneeds of a particular situation.

FIG. 4 illustrates another example embodiment of this invention. In thisexample, drive modules 40A and 40B both engage only the first side 50 ofthe step chain loop 30. A synchronizing module 60 includes asynchronizing member 62 that engages both sides 50 and 52 of the stepchain loop 30. The synchronizing module includes free-wheeling sheaves64 and 66 that support the synchronizing member 62 for proper engagementwith the step chain 30. The synchronizing module 60 transfers force fromthe second side to the first, but does not add any power to the stepchain system. Such an arrangement allows for utilizing smaller drivemodules, because they do not have to engage both sides of the chainloop. In an arrangement such as illustrated in FIG. 4, any number ofdrive modules may be used.

In one example, the synchronizing module 60 includes a synchronizingmember 62 that corresponds to the drive members 46A and 46B (i.e., aurethane-coated belt). The synchronizing member 62 preferably has anexterior surface that is contoured to provide the appropriate engagementwith the step chain. Those skilled in the art who have the benefit ofthis description will be able to select or design a synchronizing memberto meet the needs of their particular situation.

FIG. 5 illustrates another example embodiment of this invention. In thisexample one drive module 40 moves the step chain loop 30 by engagingonly the first side 50 of the step chain. A synchronizing module 60′includes a synchronizing member 62 that engages both sides 50 and 52 ofthe step chain loop 30. In this example, a plurality of sheaves 64, 66,68 and 70 support the synchronizing member 62 so that appropriateengagement with the step chain is achieved. The sheaves 64-70 may besupported by the truss structure in a conventional manner so that theyallow the synchronizing member 62 to move responsive to movement of thestep chain 30 thereby transferring force from the second side to thefirst without adding any power to the step chain system.

The preceding description is exemplary rather than limiting in nature.Variations and modifications to the disclosed examples may becomeapparent to those skilled in the art that do not necessarily depart fromthe scope of this invention. The scope of legal protection given to thisinvention can only be determined by studying the following claims.

1. A passenger conveyor system, comprising: a plurality of steps thatare moveable along a step loop having a passenger side and a returnside; a step chain associated with the steps and that is moveable alonga chain loop having a first side corresponding to the passenger side ofthe step loop and a second side corresponding to the return side of thestep loop; at least one drive module having a motor and a drive memberthat engages the step chain only on one of the first side or the secondside of the chain loop to cause selective movement of the chain and thesteps.
 2. The system of claim 1, including a second drive module havinga motor and a drive member that engages the step chain on both sides orthe chain loop.
 3. The system of claim 1, including a synchronizingmodule having a synchronizing member that engages the step chain on bothsides of the chain loop.
 4. The system of claim 3, including a seconddrive module having a motor and a drive member that engages the stepchain only on the first side of the chain loop.
 5. The system of claim1, wherein the at least one drive module engages only the first side ofthe chain loop and wherein the first side corresponds to a passengerside of the loop.
 6. The system of claim 1, wherein the at least onedrive module includes a drive sheave that moves the drive memberresponsive to the motor and the sheave has an outside dimension thatleaves spacing between the step chain loop second side and the drivemember.
 7. The system of claim 1, wherein the drive member comprises adrive belt.
 8. The system of claim 7, wherein the belt comprisesload-bearing cords imbedded in a urethane material.
 9. The system ofclaim 1, including a truss structure comprising a first material andwherein the step chain links comprise a second material.
 10. The systemof claim 6, including a second drive module including a drive memberthat engages the step chain on both sides of the chain loop.
 11. Thesystem of claim 6, including a synchronizing module having asynchronizing member that engages the step chain on both sides of thechain loop.
 12. The system of claim 11, including a second drive moduleincluding a drive member that engages the step chain only on the firstside of the chain loop.
 13. The system of claim 6, wherein the drivemember comprises a non-metallic belt.
 14. The system of claim 6including a truss structure made from a first metal material and whereinthe step chain links are made from a second metal material.
 15. A methodof moving a passenger conveyor step chain along a loop having two sides,comprising the steps of: providing a drive module having a drive memberadapted to engage the step chain; and engaging the drive member to onlyone side of the step chain loop
 16. The method of claim 15 includingproviding a second drive module having a drive member and engaging thesecond drive member to both sides of the step chain loop
 17. The methodof claim 15, including providing a synchronizing member and engaging thesynchronizing member to both sides the chain loop.
 18. The method ofclaim 15, wherein the engaging step comprises engaging the drive memberto only the passenger side or the step chain.